1. Field of the Invention
The invention relates to a process for preparing products of the reaction of polyaspartimide and amino acids and to the use of the reaction products as additive-to-detergents and cleaners, as scale inhibitor and as dispersant.
2. Description of the Related Art
The preparation of polyaspartimides by thermal polymerization of aspartic acid in the presence or absence of other amino acids is disclosed, for example, in U.S. Pat. No. 3,052 655, DE-A-4 023 463 and U.S. Pat. No. 5,057,597.
DE-A-2 032 470 discloses a process for preparing polyaspartic acid hydroxylamides by reacting polyaspartimides with alkanolamines in a solution of dimethylformamide or dimethyl sulfoxide. The reaction products are used as plasma expenders.
DE-A-2 253 190 discloses the use of polyaspartimides reacted with long-chain alkylamines as surfactants in detergents. The reaction is carried out in dimethylformamide as solvent.
J. Med. Chem. 16. (1973) 893 describes the preparation of products of the reaction of polyaspartimides and ethanolamine and the use of the reaction products as plasma expanders.
EP-A-0 406 623 discloses the use of the products of the reaction of polyaspartimides with amino compounds as coating agents and/or release-slowing agents for pharmaceutical forms of therapeutic agents and for foodstuffs and other consumables. The reactions are carried out in dimethylformamide as solvent.
As is evident from the abovementioned prior art, the reaction of polyaspartimide is carried out in solvents such as dimethylformamide or dimethyl sulfoxide. The removal of these solvents from the reaction products is industrially elaborate. In addition, dimethylformamide is toxic, not least embryotoxic.